phy: renesas: r8a779f0-ether-serdes: add USXGMII mode

The initial driver implementation was limited to SGMII and 1GBit/s. The
new mode allows speeds up to 2.5GBit/s on R-Car S4-8 SOCs.

Signed-off-by: Michael Dege <michael.dege@renesas.com>
Link: https://lore.kernel.org/r/20250703-renesas-serdes-update-v4-1-1db5629cac2b@renesas.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: mdege

drivers/phy/renesas/r8a779f0-ether-serdes.c

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Renesas Ethernet SERDES device driver
  *
- * Copyright (C) 2022 Renesas Electronics Corporation
+ * Copyright (C) 2022-2025 Renesas Electronics Corporation
  */
 
 #include <linux/delay.h>
@@ -92,17 +92,18 @@ r8a779f0_eth_serdes_common_setting(struct r8a779f0_eth_serdes_channel *channel)
 {
 	struct r8a779f0_eth_serdes_drv_data *dd = channel->dd;
 
-	switch (channel->phy_interface) {
-	case PHY_INTERFACE_MODE_SGMII:
-		r8a779f0_eth_serdes_write32(dd->addr, 0x0244, 0x180, 0x0097);
-		r8a779f0_eth_serdes_write32(dd->addr, 0x01d0, 0x180, 0x0060);
-		r8a779f0_eth_serdes_write32(dd->addr, 0x01d8, 0x180, 0x2200);
-		r8a779f0_eth_serdes_write32(dd->addr, 0x01d4, 0x180, 0x0000);
-		r8a779f0_eth_serdes_write32(dd->addr, 0x01e0, 0x180, 0x003d);
-		return 0;
-	default:
-		return -EOPNOTSUPP;
-	}
+	/* Set combination mode */
+	r8a779f0_eth_serdes_write32(dd->addr, 0x0244, 0x180, 0x00d7);
+	r8a779f0_eth_serdes_write32(dd->addr, 0x01cc, 0x180, 0xc200);
+	r8a779f0_eth_serdes_write32(dd->addr, 0x01c4, 0x180, 0x0042);
+	r8a779f0_eth_serdes_write32(dd->addr, 0x01c8, 0x180, 0x0000);
+	r8a779f0_eth_serdes_write32(dd->addr, 0x01dc, 0x180, 0x002f);
+	r8a779f0_eth_serdes_write32(dd->addr, 0x01d0, 0x180, 0x0060);
+	r8a779f0_eth_serdes_write32(dd->addr, 0x01d8, 0x180, 0x2200);
+	r8a779f0_eth_serdes_write32(dd->addr, 0x01d4, 0x180, 0x0000);
+	r8a779f0_eth_serdes_write32(dd->addr, 0x01e0, 0x180, 0x003d);
+
+	return 0;
 }
 
 static int
@@ -155,6 +156,42 @@ r8a779f0_eth_serdes_chan_setting(struct r8a779f0_eth_serdes_channel *channel)
 		r8a779f0_eth_serdes_write32(channel->addr, 0x0028, 0x1f80, 0x07a1);
 		r8a779f0_eth_serdes_write32(channel->addr, 0x0000, 0x1f80, 0x0208);
 		break;
+
+	case PHY_INTERFACE_MODE_USXGMII:
+		r8a779f0_eth_serdes_write32(channel->addr, 0x001c, 0x300, 0x0000);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x0014, 0x380, 0x0050);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x0000, 0x380, 0x2200);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x001c, 0x380, 0x0400);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x01c0, 0x180, 0x0001);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x0248, 0x180, 0x056a);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x0258, 0x180, 0x0015);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x0144, 0x180, 0x1100);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x01a0, 0x180, 0x0001);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x00d0, 0x180, 0x0001);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x0150, 0x180, 0x0001);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x00c8, 0x180, 0x0300);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x0148, 0x180, 0x0300);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x0174, 0x180, 0x0000);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x0160, 0x180, 0x0004);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x01ac, 0x180, 0x0000);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x00c4, 0x180, 0x0310);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x00c8, 0x180, 0x0301);
+		ret = r8a779f0_eth_serdes_reg_wait(channel, 0x00c8, 0x180, BIT(0), 0);
+		if (ret)
+			return ret;
+		r8a779f0_eth_serdes_write32(channel->addr, 0x0148, 0x180, 0x0301);
+		ret = r8a779f0_eth_serdes_reg_wait(channel, 0x0148, 0x180, BIT(0), 0);
+		if (ret)
+			return ret;
+		r8a779f0_eth_serdes_write32(channel->addr, 0x00c4, 0x180, 0x1310);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x00d8, 0x180, 0x1800);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x00dc, 0x180, 0x0000);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x0000, 0x380, 0x2300);
+		ret = r8a779f0_eth_serdes_reg_wait(channel, 0x0000, 0x380, BIT(8), 0);
+		if (ret)
+			return ret;
+		break;
+
 	default:
 		return -EOPNOTSUPP;
 	}
@@ -179,6 +216,14 @@ r8a779f0_eth_serdes_chan_speed(struct r8a779f0_eth_serdes_channel *channel)
 			return ret;
 		r8a779f0_eth_serdes_write32(channel->addr, 0x0008, 0x1f80, 0x0000);
 		break;
+	case PHY_INTERFACE_MODE_USXGMII:
+		r8a779f0_eth_serdes_write32(channel->addr, 0x0000, 0x1f00, 0x0120);
+		usleep_range(10, 20);
+		r8a779f0_eth_serdes_write32(channel->addr, 0x0000, 0x380, 0x2600);
+		ret = r8a779f0_eth_serdes_reg_wait(channel, 0x0000, 0x380, BIT(10), 0);
+		if (ret)
+			return ret;
+		break;
 	default:
 		return -EOPNOTSUPP;
 	}